(1) Field of the Invention
The present invention relates generally to hand tools and, in particular, to a new and novel cable stripping tool.
(2) Description of the Prior Art
It is the general practice in the construction industry to strip insulation from electrical cables and wires by cutting or scraping usually with a pocket knife. However, in cables having an outer plastic sheath and two or more insulated, stranded or solid wires, there is a danger of knicking or otherwise damaging the insulation on the inner wires. This method is slow and time-consuming, requires a certain degree of skill before becoming proficient, and often results in irritating cuts to the user's fingers. In addition, this method is even more difficult when there is a need to strip a cable inside of confined spaces, such as light switch and receptacle boxes.
U.S. Pat. No. 2,054,973 to Ferguson discloses a tool for stripping insulation from electrical wires. The Ferguson tool is a plier-like tool which allows an increase in the mechanical advantage over a simple handle-type. A first cut is made in the insulation surrounding the stranded or solid wire with the semi-circular cutting edges of a pair of opposed circular cutters. The cutters then stay in contact with the insulation as the tool is drawn away from the cut to strip the insulation from the wire. This has a tendency to "bunch up" the insulation, thereby increasing the amount of force necessary to remove the insulation. This can result in damage to the stranded or solid wire. In the preferred embodiment, the Ferguson tool includes a pair of side-slitting blades which have a tapered lead-in for slitting the sides of the insulation.
U.S. Pat. No. 4,594,921 to Ishmael discloses a coaxial cable stripping tool in which a pair of blade-shaped heating elements are clamped against opposite sides of the cable and the cable rotated to form a circumferential cut in the insulation. The cable is then placed in another jig with a V-shaped groove therein and a second blade-shaped heating element at the bottom of the groove. A second similar heating element is arranged above the groove in the cable. The two heating elements then produce diametrically opposed longitudinal cuts in the insulation, after which the two pieces of cable insulation can be removed. The circumferential cut requires that the cable and tool be rotated with respect to one another. In addition, the cable must be physically removed from the jig before the blades are free of the conductors.
The Kaufman patent (U.S. Pat. No. 3,881,248), Bradley patent (U.S. Pat. No. 3,180,184), and Sibley patent (U.S. Pat. No. 698,567) are all examples of other cross-cutter type stripping tools. However, like the above patents, all these patents teach a "chopping-cutting" arrangement in which, after cutting opposite sides of the conductor, the blades remain in contact with the insulation while the insulation is removed. Furthermore, this cutting arrangement requires a different opening size for each size cable in order to prevent damage to the wires inside the cable.
It has thus become desirable to develop a cable stripping tool that will easily remove the outer plastic sheath of the cable in a confined space such as a light switch box while, at the same time, prevent damage to insulation on the inner stranded or solid wire by either bunching up the insulation or otherwise stressing the inner stranded or solid wires such as by conventional "chopping" type strippers. Furthermore, the tool should be able to cut more than one side of cable without damaging the wires inside the cable.